Wales coach Warren Gatland will run the rule over several uncapped players in this week's senior 'trial' match.
Respective coaches Rob Howley and Robyn McBride have now named their teams for Friday's game between the 'Probables' and 'Possibles' at Swansea's Liberty Stadium.
Howley has included one uncapped player in Scarlets wing Jordan Williams in his XV with three more on the bench in Newport Gwent Dragons back-row Lewis Evans, Ospreys' Sam Davies and Cardiff Blues centre Dafydd Hewitt.
McBryde's 'Possibles' side features two uncapped players in the starting pack, in Scarlets prop Rob Evans and former Wales Under-20 skipper Ellis Jenkins.
The match will be a final hit-out for the players from Welsh regions before Gatland names his squad for the two-Test tour of South Africa next month.
A number of players based with English clubs were included in the initial squads for the trial game but they have not been released to play.
They include George North of Aviva Premiership finalists Northampton and Bath's Gavin Henson.
Several experienced players, most notably Wales captain Sam Warburton, Leigh Halfpenny, Scott Williams and Rhys Priestland, will not be involved this summer because of injury.
For the 'Probables', Jordan Williams joins an experienced back division that also includes British and Irish Lions quartet Mike Phillips, Jamie Roberts, Jonathan Davies and Alex Cuthbert, as well as RaboDirect PRO12 player of the year Dan Biggar and Scarlets full-back Liam Williams.
The front row of Gethin Jenkins, Ken Owens and Adam Jones share 223 Wales caps while captain Alun Wyn Jones, Luke Charteris, Josh Turnbull, Aaron Shingler and Taulupe Faletau make up the pack.
Josh Navidi, Rhodri Williams, Scott Baldwin, Samson Lee and Aaron Jarvis are the other replacements.
In the 'Possibles' side, captain Matthew Rees, Rhodri Jones, Jake Ball, Ian Evans, Andrew Coombs and Dan Baker will join Rob Evans and Jenkins in the pack.
PRO12 top try-scorer Gareth Davies will partner James Hook at half-back with Steven Shingler - facing his brother Aaron - and Cory Allen in midfield. Harry Robinson and Kristian Phillips are named on the wings with Dan Fish at full-back.
The bench features Cardiff Blues front-rows Kristian Dacey and Scott Andrews alongside Owen Evans, James Davies - another player who could face his brother, Jonathan - Macauley Cook, Matthew Morgan, Jonathan Spratt and Lloyd Williams.
Howley, who is Gatland's backs coach, said: "Friday is a huge opportunity for players and a chance for us to see them go up against each other for the Wales jersey.
"It's something we haven't been able to do for the last decade, but it will be a big night for the players, we want to see them in a pressured environment and that's what we will get on Friday."
Gatland is due to name his 31-man squad for South Africa after the trial match.
McBryde, the forwards coach, said: "It's been great to have the squad together. We only have a short time to prepare, but we are up for the challenge and excited by it.
"We have always said that the door is always open in international rugby and this is an opportunity that doesn't come round very often and the players know it's their chance to impress on a big public stage in front of all the coaches."